In case you’re one of those “well back in the day“ sort of persons there’s Nolan Ryan, who no one could ever accuse of not throwing hard. I don’t know if he threw every single pitch hard as he could, but anyway…
“Nolan Ryan's pitch count in a game varied, but he was known for throwing a high number of pitches, especially in longer games. He famously threw 235 pitches in a 13-inning game against the Boston Red Sox on June 14, 1974, which is a record number of pitches in a single game. In 1989, at age 42, he averaged 127 pitches per game with a high of 164.”